Shares in Thomas Cook have closed down 75% after it announced it was in talks with banks about increasing the amount of money it can borrow.

The travel firm said it had seen a "deterioration of trading", due to political unrest in Egypt and Tunisia and floods in Thailand.

It also said it would delay releasing its full year results until it had concluded the discussions.

Thomas Cook reassured customers that their bookings were fully protected.

Improving 'resilience'

Last month, Thomas Cook announced it had arranged a new £100m credit agreement with its bankers.

The company is trying to negotiate about another £100m credit.

At the end of September its net debt was just under £900m. The new loan, if agreed, would take the figure to over £1bn.

Thomas Cook said that while the last loan had taken four to six weeks to arrange, there was greater urgency this time and it was confident of being significantly quicker this time.

The company has stressed that it is not currently in breach of the terms of any of its loans, but that it wanted to "improve its resilience if trading conditions remain difficult".

Thomas Cook said last month that the terms of an existing £150m loan and an £850m credit facility have been amended to help cashflow.

Holiday protection

By Kevin PeacheyPersonal finance reporter, BBC News

While Thomas Cook's announcement is worrying for investors, there is no need for holidaymakers to share the same level of concern.

Anyone booked for an overseas package holiday with Thomas Cook is covered under the Air Travel Organisers' Licensing (Atol) scheme.

This means that even in the worst case scenario - that the company goes bust when holidaymakers are away - customers on package deals are flown home without incurring extra expense. Those who have not already left for their holiday are refunded.

Holiday bookings should also be honoured if there is a takeover.

But, at present, with Thomas Cook in talks with banks, customers need not do anything, and the company has urged those with bookings not to worry.

However, people who have only booked a flight with the company will not be covered by the Atol scheme and are advised to buy suitable travel insurance.

Thomas Cook says though that flights bought in its own stores are still Atol protected.

It is reported to be planning to close 200 of its 1,200 High Street travel agencies and bureaux de change.

'Not travelling'

In a conference call, Thomas Cook chief executive Sam Weihagen reassured customers that it was business as usual.

"We have all the protection in place as any other travel company and they should not worry," he said.

Anyone booked for a package holiday with Thomas Cook is covered under the Air Travel Organisers' Licensing (Atol) scheme, which is funded by contributions from travel companies.

However, people who have only booked a flight with the company will not be covered by the Atol scheme and are advised to buy suitable travel insurance.

Mr Weihagen explained that trading had been particularly poor in France and Belgium, where bookings are down 20% compared with last year, and in Thomas Cook's Russian business.

"Winter travellers from Russia go to Thailand or Egypt," he said, adding that the floods in Thailand and continuing political unrest in Egypt had hit those bookings.

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Media captionBrewin Dolphin's Edmund Salvesen says Thomas Cook will have to close shops to cut its debts

The biggest destination for French travellers in winter is Tunisia, which means that "the French people are simply not travelling".

He said that the trading position in the UK was "tough, but not of the same magnitude".

Thomas Cook shares have fallen 95% from their high for the year of 205 pence per share recorded in January, closing at 10p on Tuesday.

"Clearly the extremely low share price is of concern," said Mr Weihagen, adding that the company was keen to sort out the debt issues so it could then address the share price.

It has been a tough year for travel companies generally. Thomas Cook's rival Tui's shares have fallen 68% from their high for the year, including a further 5.6% fall following Thomas Cook's announcement on Tuesday.